Smoke denitration device for preventing catalyst from being plugged by popcorn ash

Abstract

The invention discloses a smoke denitration device for preventing a catalyst from being plugged by popcorn ash. The device comprises a smoke inlet (1), a horizontal connecting flue (2), a vertical connecting flue (5), a denitration reactor (7), an outlet flue (9) and a smoke outlet (10) which are communicated in sequence, wherein an ammonia spraying grating (4) is arranged in the vertical connecting flue (5); and a rectifying device (6) and a plurality of layers of catalysts (8) are arranged in the denitration reactor (7) along the smoke flowing direction. The device provided by the invention is characterized in that a metal screen (3) is arranged on the upstream of the ammonia spraying grating (4) in the vertical connecting flue (5). The smoke denitration device for preventing the catalyst from being plugged by the popcorn ash provided by the invention can be used for efficiently intercepting the 'popcorn ash' with a large grain size in the coal-fired smoke, separating the 'popcorn ash' from the smoke, and solving the problem that the catalyst is brushed and plugged by the 'popcorn ash'.

Description

technical field [0001] The invention relates to a flue gas denitrification device, and is especially suitable for an SCR flue gas denitrification device used for removing nitrogen oxides in fixed source waste gas. Background technique [0002] China is a country where coal is the main energy source. Coal accounts for 75% of the primary energy, of which more than 84% is utilized through combustion. Nitrogen oxides (NOx) in the exhaust gas released by coal combustion is one of the main sources of air pollution. Selective Catalytic Reduction (SCR) is the most common and effective method for removing nitrogen oxides in boiler exhaust gas, and is widely used in various industrial devices. The main principle is to use liquid ammonia or ammonia water as a reducing agent, mix it with air and spray it into the flue upstream of the SCR denitrification reactor, and react with the nitrogen oxides in the flue gas under the action of the catalyst to generate harmless nitrogen. and water...

AI Technical Summary

Problems solved by technology

[0003] The catalyst is usually a honeycomb or plate structure, and the flue gas completes the chemical reaction in the porous channel of the catalyst to remove the nitrogen oxides. Currently, the channel of the catalyst used in the denitrification of the flue gas of the coal-fired boiler depends on the particle size of the ash. Its size is generally about 6~10mm; on the other hand, "popcorn ash" with large particle size is usually produced in the flue gas ash produced by coal combustion, and its particle size is usually about 10~15mm, and its hardness is relatively high. , it is not easy to split into fly ash with small particle size due to the impact, if it directly enters the denitration reactor, it will wash the surface of the catalyst and block the catalyst, resulting in a decline in denitration efficiency

In the prior art, a layer of metal screen is usually arranged on the upper surface of the catalyst to intercept large particles of fly ash, such as Figure 5 As shown in , the flue gas denitration device in the prior art includes a flue gas inlet 1' connected in sequence, a horizontal section connecting the flue 2', a vertical section connecting the flue 5', a denitrification reactor 7', and an outlet flue 9' And the flue gas outlet 10', wherein the ammonia injection grid 4' is arranged in the vertical section connecting the flue 5', and the rectification device 6' and several layers of catalysts 8' are arranged in the denitrification reactor 7', above the catalyst 8' A layer of metal screen 3' is provided, so that although the direct washing of the catalyst by the "popcorn ash" with a large particle size is avoided, the "popcorn ash" still stays on the upper surface of the catalyst after being intercepted, which is of great importance to the effective passage. The flow section causes blockage, thereby reducing the denitrification efficiency; on the other hand, the screen in the prior art is usually fixed on the upper surface of the catalyst module, and due to the large particle size of the "popcorn ash", its kinetic energy is also large, and the long-term The operation will cause damage to the structure of the screen, so that the large particles of fly ash cannot be effectively intercepted

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